Universal joint



, daf* 9 33 Feb. 12, 1946. w. R, BLOMGREN 2,394,890

UNIVERSAL JOINT 1 Filed Jan. 5o, 1943 43 /N ifa/vrom 42 WALTER R. /.oMGPa/v FOI? THE FIRM Patented FeltA 12, 1946 UNIVERSAL JorN'r Walter R. Blomg'ren, Los Angeles, Calif., assignor to M. Aron, Sol Aron.' and Walter R. Blomgren,

copartners doinl.r business as Pacific Works, Los Angeles, Calif.

Machine Application January 3o, 1943, serial No. 414,151

1 Claim.

My invention relates to a universal joint and, more particularly, toa novel universal joint of the type in which torque is transmitted directly froxn one element to another without the necessity of intervening torque-transmitting means.

Generally speaking, the invention includes two universal joint elements, each providing a body portion and two arm portions extending forward therefrom. The inner surfaces of the arm portions are in the form of truncated cones or frustoconical sections, each having a surface angle of substantially 90. Two such universal joint elements can be telescoped together so that the cones of one lie `between the cones of the other and are in engagement therewith. Torque can be transmitted directly from one element to the other through the surface engagement of the cones, and this is true even though the longitudinal axes of the elements are disposed out of alignment. 'I'he elements are retained in proper engaging relationship by a cross-pin means providing radially disposed pins extending into bores of the corresponding cones.

It is an object of the present invention to provide a universal joint of this type which is of increased strength and which is well adapted to quantityproduction. y

Another object of the invention is to provide such a universal joint composed of two elements which can be produced cheaply and with a minimum of machine operations.

The invention also includes among its objects the provision of a universal joint in which both elements are identical. These elements in themselves are novel and form a, part of the present invention, as does also the novel method of making such elements. f

Other objects of the invention lie in the provision of a novel cross-pin means for such a universal joint which facilitates both assembly and interconnection of the two elements.

Further objects and advantages of the invention will be evident to those skilled in the art from the following description of an exemplary embodiment of the invention.

Referring to the drawing:

Figure l is a top elevational view of the universal joint;

Figure 2 is a vertical sectional view, taken as indicated by the line 2-2 of Figurel;

Figure 3 is a cross-sectional view, taken along the line 3--3 of Figure 1;

Figure 4 is a perspective View of a universal joint element of the invention;

lFigures 5 to 8, inclusive, represent sequentially 55 ends of the arcuate cavity the steps employed in the preferred method of making a universal joint element; and

Figure 9 is a view taken generally as indicated by the line 9-9 of Figure 8, with the cutter shown in one extreme position.'

The invention employs two of the universal joint elements shown in Figure 4, these being generally indicated by the numerals I0 and I0 of Figures 1 to 3. Hereinafter, element Ill will be specifically described, as the element I0 is a duplicate thereof, and corresponding parts on the element iii' will be indicated by primed numerals.v

The elementr I0 includes a body portion i2 providing a cylindrical surface I3 and suitable means, not shown, for connection to one of the two shafts which are to be interconnected by lthe universal joint. Integral with, and extending forward from,

the body portion I2 are two arm portions I5 and f tion to provide a web which tapers forwardly.

Furthermore, the thickness of the web 20 increases toward the'junction thereof with the arm portions I5 and I 6, as will be made clear upon later reference to the method of making the universal joint element I0.

The space between the arm portions I5 and IS comprises `an arcuate cavity 25 which extends completely around the alignedfaxes of the bores' I'I and I8 except for the space occupied by the web 20. One end of this arcuate cavity 25 is bounded by the side surface 22 of the web 20 and by a rear surface 26, while the. other end of this arcuate cavity is bounded by the side surface 23 of the web 20 and by a rear surface 21. The

rearsurfaces 26 and 21 angularly meet the side Y surfaces 22 and 23 of the web 20'to provide, in effect, pockets which receive the extremities of the arm portions I5' and I6' of the other universal joint element I0'- when these elements are disposed out of axial alignment with each other. As will be apparent from the later description, the rear surfaces 26 and 2l extend outward to the cylindrical periphery of the body portion I0, being formed as smooth, uninterrupted, curved surfaces. It will be noted that theA pockets at the 25 open outward on 2 the cylindrical surface I3, without obstruction at or near this cylindrical surface.

'I'he .arcuate cavity ..25 is also bounded by the inner surfaces of the arm portions I5 and I6.. These inner surfaces of the arm portions arev provided by truncated cones 30 and 3l so that each of these inner surfaces is in the shape of a truste-conical section. Preferablm the apex ansie of these truncated cones is substantially 90,

so that the truncated cones of the element l can be telescoped or intermeshed with the correspond' ing truncated cones 30' and 3l of the element l0' to'fcrm an interlocking structure, suggested) in Figure 3. Ii the apex angle of each truncated cone is substantially 90, these cones will be in line contact at the section 3 3, as illustraedin Figure 3.. Usually, only sufficient play is provided to permit change in the angularrelationship between the elements l0 and l0', without producing i6 are smooth" continuations of the cylindrical surface I3, the element l0 can be formed of bar 4 stock and all machine operations, such'as would be required to form indentations, are eliminated. The common axis of the aligned bores' il and lil intersects transversely the longitudinal axis of the element i3. Il'liese hores are of the same diameter, both in the elements l@ and lu'. Such bores intersect the truncated cones 3b and 3l at a relatively sharp edge, 'though this edge can be rounded ou slightly without substantially decreasing the torsional strength oi the universal joint.

The extreme forward ends of the arm portions l5 and there preferably curved. inward toward 'the longitudinal axis of the elementY lll to provide curved surfaces 33 and 3d, as best shown in Figures 2 and 4.. The curve of the surface 33,'forv example, is preferably such as to intersect the truncated cone 3u at its base in a planesubstantially parallel to the longitudinal' axis and to provide a forward periphery 35 of the arm portion l5 which is substantially concentric with the axis of the bore l1, when viewed as in Figure 1 through an angular distance greater than 180 and preferably in the neighborhood of about 240-260. A corresponding forward periphery 35 is provided stood, however, that the curved surfaces 33 and 3l Could be eliminated, if desired, Withut departing from the spirit of the'invention, in which event the arm portions I5 and l5 will present external surfaces of a cylindrical nature which -extend to the li'orward periphery 35 and 3l.

The exact nature of the contours of the walls bounding the arcuate` cavity can be understood even better by a description of the method of Amaking these elements. s

As suggested in Figure 5, the iirst step is to cut a bar of cylindrical stock 38 to the desired length. Thereafter, a transverse and the end diameter reduced progressively as l suggested in Figure '7.

The final' step involved is the cutting of the arcuate cavity 25. This may be accomplished by i pivotally mounting the stock 38 on a stationary by the arm portion I6. When the universal joint is flexed in maximum degree, the forward periphery 35, for example, extends substantially to the line of obtuse intersection of the side surface 23.

and .the rear surface 21', as can best be determined fromv Figure 2. At the same time, the curved surface 34 of the arm portion I6, which now tends to protrude from its corresponding pocket of the cylindrical cavity 25, prevents any such degree of extension of this arm portion as might represent a hazard if the universal joint is rotating. The curved surfaces 33 and 34 are also important in permitting the relatively large degree of angular displacement permissible with the universal joint of the invention, while still permitting the use of a. web 20 of sufllcient thickness to serve as a substantial reinforcement for the arm portions I5 and I6. It should be underarbor 40, extending into the bore 39 and mounted in a suitable base plate or jig. A double-conical milling cutter 4| is employed for the cutting operation. As best shown in Figures 8 and 9, itincludes a forward conical cutting portion 42 and a rearward conical cutting portion 43 formed base-to-base as apart of the cutter #l l. The apex angle of the forward conical cutting portion 32 is substantially though the apex angle of the rearward conical cutting portion 43 is usually less than 90. With the stock 38 mounted on the arbor d0, the rotating cutter M is advanced to. Ward the stock, or vice versa, to produce the type of cut suggested in Figure S. Thereafter, the stock 33' can be slowly pivoted about the arbor tu, first in one direction and thenin the other to produce the arcuate cavity 25. Alternatively, it should be understood that the stock 33 ycan be fixed-to the arbor lu and the cutter di revolved about `the axis of the arbor to produce the arcuate cavity 25. ,In either instance, there will be rear conical cutting portion 43 also comes intoA play to cooperate -with the forward portion in f ormingfthe pocket at the end of the arcuate cavity 25. The curves of the side surface 22 of the web 20 and of the rear surface 26, `for example, are thus simultaneously determnedby the cutting action of the teeth of the cutter Il. The

peripheral length of the rear-conical cutting por' tion 43 is suiiicient to extend completely to the cylindrical surface of the stock. By relative motion of the stock 38 and the cutter 4I to the extreme position, the opposite pocket will be formed. These operations automatically form the web 20.

In assembling two of the universal joint .elements, it is necessary to provide a pivot means for retaining the truncated cones in proper relationship. 'I'his pivot means is shown generally in Figures 1,72, and 3 as comprising a crossshaped pin means providing, in effect, four radially extending pins which extend respectively into the aligned bores I1, I'I', I8, I8' of the four arm portions I5, I5', I6, I8'. The preferred construction of this cross-shaped pin means is best shown in Figures 2 and 3. A first pin, 5|-, of cylindrical shape, is disposed to extend through the aligned bores Il' and I8', being oi a diameter only slight- 1y smaller than the bores so as to be pivotable therein. This iirst pin II provides a transverse bore 52 in the space between the truncated cones 30 and 3|. A second pin 5I providesa head Il and a reduced-diameter shank 55, the latter extending through the transverse bore 52. The head 54 is of a diameter to pivot in the bore I8, while the end of the shank extends through the aligned bore Il. A sleeve 51 surrounds the shank 55 and is of such diameter as to pivot within the' responds in curvature to, and partially envelops,

the periphery oi.' the first pin 5I, as suggestedin Figure 2 where the curved surface of the sleeve is indicated by the numeral 58. To avoid any interierence between the inner end of the sleeve and the' webs 20 and 20' upon maximum flexure of the universal joint, this inner end of the sleeve is preferably beveled, as indicated by the numeral 6l, to form a continuation of the truste-conical surface of the adjacent truncated cone. Also, the sleeve 51 should be maintained in contact with the pin 5| and this can be accomplished by providing an obstruction on the end of the shank 5B engaging the sleeve l1. For example, the outer end oi' this sleeve may be countersunk, as indicated by the numeral 6I and the outer end of the shank 55 can be deformedby peening to spread in the counter-bore and provide a head 62. This operation is the o nly one required to It will be apparent that this type oi universal joint can be rapidly manufactured with a minimum of parts. At the same time, it requires only a very simple operation to assemble the elementsmaking up the universal joint. 'I he resulting universal joint ls very strong in tension or torsion. With regard to the torsional strength, it will be apparent that transmission of torque is effected by actual engagement of the truncated v cones and that the cross-pin means carries substantially none of this torque, serving primarily to hold the universal joint elements in proper relationship and to determine the proper pivoting relationship therebetween.

Various changes can be made without depart.- ing from the spirit of the invention as defined in the appended claim.

I claim as my invention:

A universal joint including a cooperating pair of joint elements. each including a body portion having a cylindrical surface, a pair of arms inlock all elements o! the universal joint together.

Preferably, the heads Il and B2, and the ends of the pin 5I, are substantially flush with the surfaces or their respective arm portions.

tegral with each body portion and extending axially forward thereof, said arms being formed with bores which are disposed in axial alignment with each other and each arm providing an external surface which is a smooth unnotched continuation of said cylindrical surface from said body portion substantially to the bore of the arm, a web extending between said arms and formed integrally therewith, the space between said arms comprising an arcuate cavity, opposed frustoconical surfaces formed on the inner ends of said arms coaxially of said bores and bounding said arcuate cavity on the opposite sides of said web, and pins extending through said aligned bores for connecting'said elements for universal movement, each en d of said arcuate cavity com- A prlsing a surface o! said web and an arcuate end wall extending outwardly therefrom at an angle sumcient to provide a ilarlng passage open to the juncture of the weband end wall in any angular relation to the joint elements.

. y WALTER R. BLOMGREN. 

